Duplicate rows in pandas DF

Question

I have a DF in Pandas, which looks like:

Letters Numbers
A       1
A       3
A       2
A       1
B       1
B       2
B       3
C       2
C       2
         


        

Answer 1

You can groupby these two columns and then calculate the sizes of the groups:

In [16]: df.groupby(['Letters', 'Numbers']).size()
Out[16]: 
Letters  Numbers
A        1          2
         2          1
         3          1
B        1          1
         2          1
         3          1
C        2          2
dtype: int64

To get a DataFrame like in your example output, you can reset the index with reset_index.